The College gives over 140 free public lectures every year. Since 2001, all lectures have also been made available online.
The college played an important role in the Enlightenment and in the formation of the Royal Society. Early distinguished Gresham College professors included Christopher Wren, who lectured on astronomy in the 17th century, and Robert Hooke, who was Professor of Geometry from 1665 until 1704.
The professors received £50 a year. The terms of their position were very precise, for example: :The geometrician is to read as followeth, every Trinity term arithmetique, in Michaelmas and Hilary terms theoretical geometry, in Easter term practical geometry. The astronomy reader is to read in his solemn lectures, first the principles of the sphere, and the theory of the planets, and the use of the astrolabe and the staff, and other common instruments for the capacity of mariners.
Today three further Professorships have been added to take account of areas not otherwise covered by the original Professorships:
- Commerce, established in 1985.
- Environment, established in 2014.
- Information technology, established in 2015.
The professors currently hold their positions for three years, extendable for a fourth year. They give six lectures a year. There are also visiting professors appointed to give series of lectures at the College. There are a number of single-lecture speakers.
The lectures are often given in the Museum of London, which has a bigger lecture room than the College.
- "Gresham Professor of Geometry". gresham.ac.uk.
- "Who invented the calculus? – and other 17th century topics" Archived 28 September 2007 at the Wayback Machine Gresham lecture by Robin Wilson, 16 November 2005. Retrieved 16 February 2006.
- "Gresham College". mercers.co.uk.
- "Gresham Professor of the Environment: Carolyn Roberts appointed to only the second new Professorship in 400 years" Archived 25 September 2015 at the Wayback Machine, Gresham College press release, 25 June 2014 (accessed 27/07/15)
- "Elizabethan "University" Appoints Professor of IT", Gresham College press release, 26 June 2015 (accessed 27/07/15)
- "Profile of Gresham College". uk-universities.net.